Clot (7)
There are a few possibilities for this:
coagulate
(Other definitions for thicken that I've seen before include "Make dense" , "Clot" , "Become more viscous" , "Become more involved" , "(Of a plot) become more complicated" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">clot</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for congeal that I've seen before include "Become solid" , "Set - go clean (anag)" , "Cool and solidify" , "Jell" , "Become gelatinous" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">clot</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for coagulate that I've seen before include "Clot in catalogue" , "Congeal" , "Thicken or clot, like blood" , "(Of blood) solidify" , "Change from liquid into semi-solid as in catalogue" .)